In the past, there have been motor devices mounted in vehicles such as automobiles to be used as drive sources of power window devices or power seat devices. In-vehicle motor devices are installed in narrow spaces such as an inside of a door or an inside of a seat cushion. For this reason, miniaturization and better layout properties of motor devices have been demanded.
Patent Literature 1, for example, has disclosed such an in-vehicle motor device (a motor). The motor disclosed in Patent Literature 1 includes a motor main body constituting a pair of cases and a deceleration unit, and the components are brought in contact with each other to become one piece. A yoke housing of the motor main body houses a rotor having a commutator such that the rotor can freely rotate. Meanwhile, a gear housing of the deceleration unit houses a worm shaft which is rotated by the rotor and a worm wheel which is rotated by the worm shaft.
In addition, a brush holder is provided in a space between the yoke housing and the gear housing. The brush holder has a holder main body holding a brush and a power supply unit which is provided to be exposed to the outside of the motor device and supplies a drive current to the brush. Thus, when an external power source supplies a drive current to the power supply unit, the rotor rotates. The rotation of the rotor is transmitted from the worm shaft to the worm wheel, a speed thereof thus decreases, and a rotation force having high torque is output from an output shaft of the worm wheel to the outside.